Environmental lighting, particularly outdoor lighting, is well known in commercial or public settings such as parks and schools. Such lighting is also popular in residential applications, both to enhance the appearance and safety of the outdoor area and for security, to illuminate dark areas around a building or in a yard which may provide hiding places and unobserved entry points for intruders.
Conventional landscape and outdoor lighting systems include one or more lighting fixtures which are connected to either a 12 V transformer or a standard 120 VAC line. Some lighting fixtures enclose a halogen lamp or incandescent bulb within a housing, and include a reflector assembly and a lens or window within the housing. These fixtures may be used for highlighting features such as trees or statues, i.e., up-lighting or for pathway or ground lighting.
As technology has advanced and “green” technologies have become more cost-efficient to manufacture, LED lighting systems are becoming more popular as replacements for existing lighting systems. LED components use five to ten times less energy than a fluorescent light and produce significantly more lumens for a given input energy level. In addition to the energy savings from lower power consumption in conventional low voltage lighting systems, LEDs are especially important for use in solar-based lighting systems, where energy efficiency is essential to maximize the period of illumination produced by the stored charge in one or more batteries connected to the photovoltaic solar panel. Due to their solid state construction, LED light sources tend to be more durable and have much longer lives than more traditional lighting solutions such as incandescent and fluorescent lighting. LEDs are versatile in their ability to deliver virtually any color light by combining different red, blue and green arrays. LEDs are ecologically desirable since, unlike their fluorescent counterparts, they contain no lead or mercury. These and other benefits associated with LEDs make them attractive replacements for conventional incandescent, halogen and fluorescent light sources in many applications, including outdoor lighting systems.
One drawback of LEDs is that due to the relatively intense light that is generated across a very small surface area, thermal management becomes a major issue. Unless this heat is properly dissipated, the lifespan of the LED may be greatly reduced. To provide heat management, conventional LED light devices often incorporate heat sink components. In some prior art devices, an LED is mounted on a printed circuit board (PCB) which has holes through which solder or metal paste is flowed to conduct heat from the LED to the air or to a metal slug that conducts heat away from the PCB. In addition, driver circuitry is required for providing input voltage to the LED. The driver circuit, which includes integrated circuits (op-amps and/or transistors) resistors, capacitors, diodes and inductors, protects the LEDs from excessive current by pulsing the input voltage. The driver also regulates the light output. The LED driver is frequently configured in a single module as a can or disk with wires extending from it to allow for connection to an input voltage source, e.g., batteries or cable connected to a lighting system transformer, and to the PCB on which the LED is mounted. The LED driver is usually encapsulated in an epoxy potting material to protect the circuitry from harsh environments and moisture. In an outdoor lighting fixture, the LED driver will often be housed within the post or stem of the fixture, at a distance from the LED light device. This tends to make connection of the LED to the driver a challenge, particularly when the LED must be replaced.
Accordingly, placing an LED lighting component with its circuitry inside lighting fixtures and other structures can be daunting with various space constraints, thermal management and electrical incompatibility. As a result, lighting fixtures utilizing LED light sources are not readily available in conventional outdoor lighting systems.
Thus, the need remains for an outdoor light fixture that is attractive, uses an LED lighting component, is easy to manufacture and service, and may be used to retrofit conventional lighting fixtures. The present invention is directed to such a device.